问题:通过HttpUrlConnection获取网站数据 ,
描述:参照书本的例程.xml和.java如下,并已在AndroidManifest.xml文件中添加了
<uses-permission android:name="android.permission.INTERNET"/> 但模拟运行程序时,点击button并无数据返回显示,想请教下应该如何解决?
.java文件
package com.example.onenet_block_get;
import androidx.appcompat.app.AppCompatActivity;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.util.Log;
import android.view.Menu;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
public class MainActivity extends AppCompatActivity implements View.OnClickListener {
TextView responseText;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.testget);
Button sendRequest = (Button) findViewById(R.id.send_request);
responseText = (TextView) findViewById(R.id.reponse_text);
sendRequest.setOnClickListener(this);
}
public void onClick(View v) {
if (v.getId() == R.id.send_request) {
sendRequestWithHttpURLConnection();
}
}
private void sendRequestWithHttpURLConnection() {
new Thread(new Runnable() {
@Override
public void run() {
HttpURLConnection connection = null;
BufferedReader reader = null;
try {
URL url = new URL("http://www.baidu.com");
connection = (HttpURLConnection) url.openConnection();
connection.setRequestMethod("GET");
connection.setConnectTimeout(8000);
connection.setReadTimeout(8000);
InputStream in = connection.getInputStream();
reader = new BufferedReader(new InputStreamReader(in));
StringBuilder response = new StringBuilder();
String line;
while ((line = reader.readLine()) !=null ) {
response.append(line);
}
showResponse(response.toString());
}catch (Exception e){
e.printStackTrace();
}finally {
if(reader != null) {
try {
reader.close();
}catch (IOException e) {
e.printStackTrace();
}
}
if(connection != null) {
connection.disconnect();
}
}
}
}).start();
}
private void showResponse(final String response) {
runOnUiThread(new Runnable() {
@Override
public void run() {
responseText.setText(response);
}
});
}
}
.xml文件
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="match_parent"
android:layout_height="match_parent">
<Button
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="@+id/send_request"
android:text="Send Request"/>
<ScrollView
android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="@+id/reponse_text"/>
</ScrollView>
</LinearLayout>
将原有代码
URL url = new URL("http://www.baidu.com");
修改成
URL url = new URL("https://www.baidu.com");